Apparatus and method for modifying an object

ABSTRACT

A method and apparatus includes positioning a reactant on a surface in specific location and then directing an energy source from a device at the reactant such that it modifies the surface to either remove material or add material.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and is a continuation application ofU.S. patent application Ser. No. 11/415,203, filed May 2, 2006, which isa continuation of U.S. patent application Ser. No. 11/047,877, filedFeb. 2, 2005, now U.S. Pat. No. 7,323,699, issued Jan. 29, 2008, thedisclosure of which is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to the alteration of materialwith a relative high degree of volumetric and positional accuracy. Morespecifically, the present invention relates to the removal and additionof material from substrates and items used in the semiconductor industrysuch as in the modification of semiconductor wafers and photomasks,which are used in photolithography process, the creation ofsemiconductors and micro and nano structures. The invention can makesubstrate alterations with dimensions in the nanometer and larger rangeand relative to surfaces and surface features with nanometer positionalaccuracy (X, Y and Z).

BACKGROUND OF THE INVENTION

In modifying and fabricating wafers, semiconductor die, photomasks andflat panel display/microdisplay devices for the semiconductor industryand other industries as well as correcting defects in masks used forprocessing of semiconductors, it is sometimes necessary to create smallholes and other shapes that are relatively deep compared to theirdiameter or surface area. It is also sometimes necessary to create smallholes and shapes relative to other device features with a highpositional accuracy. With regard to holes, high aspect ratio holes aredifficult to create. Note that, the ratio of the depth to width isreferred to as the aspect ratio.

Attempts to overcome the difficulty associated with high aspect ratiostructures have been relatively unsuccessful. Generally, these solutionseither bore material out of the sample using particle beams such as ionbeams, electron beams or laser beams. For example, U.S. Pat. No.6,403,388 to Birdsley et al. discloses a method of using ion beams forthis purpose. Such beam devices are also used to deposit material on thesample surfaces by introducing gasses into the beam. However, there aredistinct disadvantages with these solutions.

U.S. Pat. No. 6,827,979, U.S. Pat. No. 6,635,311 as well as U.S. patentapplication Ser. No. 10/449,685, U.S. patent application Ser. No.10/442,188, U.S. patent application Ser. No. 10/465,794, U.S. patentapplication Ser. No. 10/301,843, U.S. patent application Ser. No.10/261,663 to Mirkin et al. teach methods of using scanning probemicroscopes to add material to objects in small dimensions. Theseteachings show chemical techniques as the mechanisms for the additiveprocess. These teaching do not include the activation of the additivematerials by the use of electromagnetic, particle beam or gaseousmaterials. The use and apparatus of activation means described by theapplicants herein results in substantially more versatility inapplicant's invention.

U.S. Pat. Nos. 6,737,646 and 6,674,074 to Schwartz disclose addingmaterial to an object by coating a tip and applying that coating to anobject with an atomic force microscope. The invention further teaches achamber for containing gasses. However, the invention has a distinctdisadvantage in that at no point is the coating or material activatedwith an energy device. By including an energy device, the time to addthe material to an object is significantly reduced.

When using ion beams to attempt material removal, the ions may imbedthemselves in the sample or device to varying depths. As a result, thedevice becomes unusable because the device properties may be changed bythe presence of the imbedded ions. The introduction of gasses into anion beam also poses additional challenges in containment in and theselection of suitable gasses in the ion beam chamber.

With electron beams, controlling the position of the beam becomesdifficult if the sample begins to develop charge. This phenomenon occurswhen the electron beam strikes a non-conductive or poorly conductivesubstrate surface. As a result, the accuracy of this method becomes aserious concern for the end user. The use of such beams can causeuncontrolled damage, which could render the target device unusable. Theintroduction of gasses into an electron beam also poses challenges inthe containment in and the selection of suitable gasses in the electronbeam chamber.

With laser light, the size of the hole may be limited by the size of theachievable focus spot. In cases where material modifications smallerthan the nominal focus spot are achieved, the depth of removal, andtherefore the aspect ratio, is limited Laser light then only becomes apartial solution with limited applications due to the limitations of thefocused light beam wavelength.

Additionally, in semiconductor processing and evaluation, physicalaccess to subsurface features may also be needed. A small diameter holeor small area for holes that are not round, is desirable to preventdestruction or damage to features in the device that are adjacent to thehole. None of the prior art solutions are able to achieve this task witha relative degree of accuracy and precision.

Accordingly, a technique that is able to modify a sample such as asemiconductor with high positional accuracy and volumetric control isneeded. There is also a need to be able to modify the semiconductor ortarget device to add material as required by the end user. There is alsoa need to be able to remove varying levels of materials without greatlyaffecting adjacent areas. The combination of high aspect ratio featureswith high positional accuracy, limits the affect to adjacent areas.

SUMMARY OF THE INVENTION

The foregoing needs are met, to a great extent, by the presentinvention, wherein in one aspect an apparatus is provided that in someembodiments permits an object such as semiconductor device to bemodified such that material is removed or added. The present inventionaccomplishes this task by placing a reactant on the device to bemodified and subjecting the reactant to a form of energy such that thereactant is able to modify the surface as desired. The reactant isuniquely selected for the desired task based upon the composition of thedevice. The energy form the mentioned source in the various embodimentsof the present invention may be light energy, acoustic energy, or energyin the form of heat. Alternately the energy may be particle beam energysuch as electrons, ions or other atomic particles. The reactant may beactivated by introducing a gas into the area around the reactant.

The reactant chosen depends on whether the need is to remove materialfrom the sample or whether material is to be added to the sample. Theaccurate placement of the reactant is typically accomplished with ascanning probe microscope. Scanning probe microscopes are a class ofmicroscopes that use a probe assembly comprising a very fine tip on aprobe. The probe assembly is guided in the X, Y, and Z directions usinga very accurate positioning mechanism. These microscopes typically makeuse of some particular interaction between the probe and the surface ofa sample. For example, a scanning tunneling microscope places a smallbias voltage between the probe tip and the sample. This microscope thendetects the currents that flow to or from the tip to the sample. Anothertype of scanning probe microscope is a scanning force microscope. Thismicroscope utilizes a very sharp tip on the probe assembly. The tip ismounted on a cantilever. Deflections of the cantilever caused by theattractive or repulsive interatomic forces acting on the tip aremonitored. Other types of scanning probe microscopes use capacitive ormagnetic detection mechanisms. The invention described here typicallyshows a scanning force microscope, but other types of scanning probemicroscopes can function equally well in many of the embodimentsdescribed.

In accordance with one embodiment of the present invention, a method formodifying an object includes positioning a reactant on the sample or anobject and directing energy towards the reactant, wherein the energy isconfigured to activate the reactant such that it modifies the sample orobject. The reactant is chosen or selected based upon the composition ofthe sample. The sample can be modified either by removing material oradding material.

In accordance with another embodiment of the present invention, anapparatus for modifying an object includes a reactant that is positionedon the object and an energy device configured to direct its output atthe reactant in order to modify the object. This embodiment can furtherinclude an assembly that is configured to position the reactant on theobject.

In accordance with yet another embodiment of the present invention, aproduct produced by the process of modifying a sample includespositioning a reactant on the sample and directing and energy sourcetowards the reactant, wherein the energy along with the reactant isconfigured to modify the sample. The sample is modified by removingmaterial or adding material.

In yet another embodiment of the invention, the reactant, when in fluidstate, may be delivered to the surface of a sample by directing orforcing the fluid reactant through a channel formed in the cantileverand tip assembly. U.S. Pat. Nos. 6,337,479 and 6,353,219 to Kley, whichare hereby incorporated by reference, describes a fluid delivery systemusing a channel in the cantilever and tip of a scanning forcemicroscope.

There has thus been outlined, rather broadly, certain embodiments of theinvention in order that the detailed description thereof may be betterunderstood, and in order that the present contribution to the art may bebetter appreciated. There are, of course, additional embodiments of theinvention that will be described below and which will form the subjectmatter of the claims appended hereto.

In this respect, before explaining; at least one embodiment of theinvention in detail, it is to be understood that the invention is notlimited in its application to the details of construction and to thearrangements of the components set forth in the following description orillustrated in the drawings. The invention is capable of embodiments inaddition to those described and of being practiced and carried out invarious ways. Also, it is to be understood that the phraseology andterminology employed herein, as well as the abstract, are for thepurpose of description and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the concept uponwhich this disclosure is based may readily be utilized as a basis forthe designing of other structures, methods and systems for carrying outthe several purposes of the present invention. It is important,therefore, that the claims be regarded as including such equivalentconstructions insofar as they do not depart from the spirit and scope ofthe present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a scanning probe microscope probe assembly with anamount of subtractive reactant on the probe tip positioned above thesurface of a target device.

FIG. 1B illustrates a scanning probe microscope probe assembly with anamount of subtractive reactant on the probe tip in proximity of thetarget device with the reactant wetting to the surface of the targetdevice surface.

FIG. 1C illustrates the target device surface with an amount ofsubtractive reactant on the surface with a light beam directed towardsthe reactant.

FIG. 1D illustrates the target device surface with a dimple that is theresult of activation of the subtractive reactant on the surface. Thisactivation is caused by the light beam.

FIG. 2A illustrates a scanning probe microscope probe assembly with anamount of additive reactant on the probe tip above the surface of atarget device.

FIG. 2B illustrates a scanning probe microscope probe assembly with anamount of additive reactant on the probe tip in proximity of the targetdevice with the reactant wetting to the surface of the target devicesurface.

FIG. 2C illustrates the target device surface with an amount of additivereactant on the surface with a light beam directed toward the reactant.

FIG. 2D illustrates the target device surface with a bump that is theresult of activation of the additive reactant on the surface. Theactivation is caused by the light beam.

FIG. 3A illustrates a scanning probe microscope probe assembly drawingan amount of reactant from a pool of reactant.

FIG. 3B illustrates the probe tip transporting an amount of reactant.

FIG. 4A illustrates a scanning probe microscope depositing reactant ontoa surface dimple resulting from a previous application of subtractivereactant.

FIG. 4B illustrates an electromagnetic source directing a beam of energytoward the reactant.

FIG. 4C illustrates the resulting void created by a second or subsequentdeposition of reactant and a stop layer of material that is not reactiveto the etchant.

FIG. 5A illustrates a scanning probe microscope depositing additivereactant on to a surface dimple resulting from a previous application ofsubtractive reactant.

FIG. 5B illustrates an electromagnetic source directing a beam of energytoward the additive reactant.

FIG. 5C illustrates the resulting partially filled void created byapplication of additive reactant on top of a stop layer of material.

FIG. 5D illustrates the resulting filled void created by application ofadditive reactant.

FIG. 6A illustrates a multi-layer device.

FIG. 6B illustrates the result of etching a hole in a sample with thehole filled with a nonconductive residue.

FIG. 6C illustrates the result of etching a hole in the nonconductiveresidue.

FIG. 6D illustrates the filled hole in the nonconductive reside. Thefill residue in this illustration is conductive.

FIG. 7 illustrates an electrostatic charge on the tip and reactant aswell as an opposite electrostatic charge on the target device.

FIG. 8A illustrates a probe tip coated with reactant.

FIG. 8B illustrates a cantilever of a probe assembly lowering the probetip to a surface of the sample.

FIG. 8C illustrates reactant deposited on the surface of the sampleafter the probe is moved away from the surface.

FIG. 9A illustrates a probe tip coated with reactant that has beendipped into a solvent liquid.

FIG. 9B illustrates a second droplet of reactant that occurs when acoated probe tip reacts with a first droplet of the reactant.

FIG. 10A illustrates a laser chemical machining system with a probeassembly that includes channels in the probe assembly for delivery offluid to the surface of the sample.

FIG. 10B illustrates the delivery of the fluid from the channel to thesurface of the sample.

FIG. IOC illustrates an energy source activating the fluid after it hasbeen deposited on the surface of the sample.

FIG. 11A illustrates placing multiple droplets of reactant on a samplesurface.

FIG. 11B illustrates activation of multiple droplets of reactant on thesample.

FIG. 11C illustrates a shape resulting from the placement and activationof droplets on a sample surface.

DETAILED DESCRIPTION

The invention will now be described with reference to the drawingfigures, in which like reference numerals refer to like partsthroughout. An embodiment in accordance with the present inventionutilizes a small amount of a liquid such as a chemical or a particle ofsolid material, which is referred to as a reactant to modify a surfaceof an object. This droplet or particle is typically placed on the sampleby a probe with a small point.

An embodiment of the present inventive apparatus and method isillustrated in FIG. IA, which shows a scanning probe microscope probeassembly with an amount of subtractive reactant on the probe tip abovethe surface of a target device. In this figure, a scanning probemicroscope probe assembly 10 includes a probe lever 12 and a probe tip14. The scanning probe microscope probe assembly 10 is used, in thepreferred embodiment, to precisely and accurately place a reactant 16 ona target device surface 18. To do this, the reactant 16, in thisinstance a subtractive or removal reactant, is placed or located on theprobe tip 14. Once it is placed on the probe tip 14, the probe tip 14,with attached reactant 16, is then moved into the desired location overand then onto the device surface 18.

The probe tip 10 can be of the type used in a probe microscope. Theaccurate positioning of such probes over and on the sample can beachieved by use of a probe microscope device. In this manner, thereactant 16 is placed on the target device surface 18 of the sample witha high degree of precision, such as to the nanometer range, relative tothe surface or surface features. The reactant 16, in the preferredembodiment, can be in the size range of from 1 square nanometer to 60square nanometers or larger.

FIG. 1B shows a scanning probe microscope probe assembly 10 with anamount of reactant 16, subtractive, on the probe tip 14 in proximity ofthe target device with the reactant wetting to the surface of the targetdevice surface 18. In the preferred embodiment of the present invention,the reactant 16 is generally in liquid form. Surface forces (i.e.surface tension and adhesion) are relied upon to cause the reactant 16to adhere to the probe tip 10 of a scanning force microscope while thereactant 16 is transported to the target device surface 18 or substrate.When reactant 16 is brought sufficiently close to surface 18 thereactant 16 will transfer to the surface 18 via capillary action. Inthis case, the tip material and the reactant 16 are selected from agroup of materials and reactants where the tip material is at leastpartially hydrophilic to the reactant 16. In addition, in this case, thesubstrate material may be hydrophilic to facilitate transfer of thereactant 16 from the tip 14 to the substrate. The selection of tipmaterial and reactant 16 in this embodiment is such that the tip 14would resist chemical reaction with the reactant 16. In subsequentembodiments the tip material and reactant would be selected such that amild or possibly strong reaction between the tip 14 and reactant 16occurs.

In an alternative embodiment of the present invention shown in FIGS. 8and 9, the probe tip 14 may contain the reactant or a component of thereactant. This is accomplished by coating the tip 60 prior to use. Inthis case, the tip, most likely, becomes a consumable in the process.Transfer of the reactant from the tip 60 is accomplished by touching thecoated tip to the surface, see FIG. 8B, which positions the reactant 62(part of the coating), see FIG. 8C. Transfer could also be accomplishedby dipping the coated tip into another component of the reactant or intoa solvent to dissolve part of the coating. This process would facilitatetransfer of the coated tip reactant 74 to the substrate surface. Again,in these embodiments, electromagnetic (EM) energy is directed at thematerial transferred to the substrate to change the transferred materialto its final desired form. For this embodiment, it is possible that thetip itself could be fabricated from the reactant material instead ofapplying a coating. Note that FIGS. 8 and 9 are described in additionaldetail herein.

In an alternate embodiment of the present invention, the transfer ofreactant 16 to and from the tip may also be facilitated by creating anelectric charge on the probe tip 14 and/or the substrate. In thisembodiment, the reactant 16 is attracted by electrostatic force to thesubstrate and a dissolved portion of the sacrificial tip is transferredto the substrate along with the reactant. In a subsequent step the EMenergy is directed at the transferred material and the transferredmaterial changes to its final state.

FIG. 1C shows the target device surface 18 with an amount of subtractivereactant on the surface 18 with a light beam directed toward thereactant. In the preferred embodiment, this light beam includes anelectromagnetic source 20 with an electromagnetic beam 22 emanatingtherefrom.

In order to remove debris that may be generated as the result ofactivating reactant 16, a gaseous transport medium 23 may be directedover sample surface 18. Alternately gaseous medium 23 may be used toactivate reactant 16 with or without the use of source 20.

According to the preferred embodiment of the present invention, afterplacement of the reactant 16 on the device surface 18, electromagneticenergy (typically derived from a laser) is directed towards the samplesurface on which the reactant 16 resides. The electromagnetic energylevel is set such that the energy is sufficient to activate chemicals inthe reactant 16 causing the chemical to etch the surface of the sampleleaving a dimple approximately the size of the droplet or particle. Byrepeated applications of reactant 16 and electromagnetic energy, thedimple can be deepened until a predetermined depth or a detected depthis reached without significant enlargement of the diameter or surfacearea of the dimple and thus create a high aspect ratio hole. During aniterative process, it can be necessary to re-register the tip relativeto surface or surface features. For example, it may be necessary toverify the depth of the removal spot to reach a specific final depth. Inthis case, the tip may be cleaned prior to verifying the position sothat residual reactant is not placed or located onto the surface. Onemethod to clean residual reactant from the tip is to dip the tip into areactant solvent that does not substantially affect the tip material.

FIG. 1D shows the target device surface 18 with a dimple 24 that is theresult of activation of the subtractive reactant 16 on the surfacecaused by the light beam 22. In this instance, the user desired toremove material that inadvertently appeared or was created during themanufacturing process. If the material was a semiconductor device, thismaterial could be an improper connection that could render the deviceinoperable. In many instances, the semiconductor device would have to bereconstructed. However, with the present invention, very small or minutefeatures on the semiconductor device are able to be fixed. In manyinstances, the features are so small that there is no other suitable wayto remove or reconstruct them. With the present invention, thesefeatures may be corrected in a substantially more accurate way and in afraction of the time.

FIG. 2A shows a scanning probe microscope probe assembly 10 with anamount of additive reactant 26 on the probe tip 14 above the surface ofa target device surface 18. The process in creating additional materialon a target device material is similar to that of removing material.

After the additive reactant 26 is on the probe tip 14, the scanningprobe microscope probe assembly 10 places or positions the additivereactant 26 in proximity of the target device surface 18 with thereactant wetting to the surface of the target device surface as in shownin FIG. 2B. The location to where the material is added, in thepreferred embodiment, is known previously to the user. The user, upondesiring to add material to a surface, selects the additive reactant inconjunction with the problem that they are trying to solve. Uponselecting the additive reactant 26, the scanning probe microscopeassembly 10 removes it from one location such as from a container to thetarget device surface 18 via the probe tip 14. If the tip materialpartially reacts to the reactant 16, then the tip may also partiallydissolve into the reactant before the transfer of the reactant to thesubstrate occurs. A portion of the tip, the sacrificial tip, maydissolve in the liquid reactant such that the dissolved portioncontributes to the build up of residue 28.

FIG. 2C shows the target device surface 18 with an amount of additivereactant 26 on the surface with the light beam directed toward thereactant 26. Once the probe tip 14 places or positions the additivereactant 26 on the target device surface 18, the additive reactant 26 issubjected to the EM beam 18 from which it begins to react and begin theformation of additive material on the surface of the target device 18.

FIG. 2D shows the target device surface 18 with a protrusion formedthereon. A bump of residue 28 is created from the activation of theadditive reactant 26 on the surface caused by the EM beam 22. Once theresidue 28 is created, the technician can create or add additionalresidue matter if needed or remove all or portions of the residue 28through the method described in FIGS. 1A-1D.

The droplet or particle leaves a residue 28 on the device after beingactivated by the electromagnetic energy. This residue 28 may act as aconductor or as an insulator. If the device is a photo-mask, the residuemay act as an absorber of light.

The source EM beam 22 is typically a laser, a noncoherent light source,or in an alternate embodiment high frequency radio waves. A laser orelectromagnetic source that is tunable over a range of wavelengths isdesirable in certain applications. With such a laser, the wavelength istuned to excite the reactant to a state whereby it would etch or removematerial of small areas on the sample or excites the reactant to a statethat would accelerate the rate of material removal.

Two mechanisms are used to remove from or deposit material on thedevice. The first, which is the preferred embodiment, is a photo-thermaleffect. In this mechanism, the reactant is excited by EM energy to causea thermal increase in the reactant. This thermal increase can cause thereactant to etch more quickly. Alternately, employing the photo-thermaleffect, the reactant may change to a solid residue that acts as aconductor, insulator, or as an opaque layer. The level of the EM energyis selected to excite the reactant to a level that increases the speedof the reactance without melting the device material.

The composition of the reactant 16 may be chosen such that it wouldenter a state of excitation sufficient to cause removal of material fromthe device in a chosen location and would not affect materialsurrounding that location.

Alternately, the composition of the reactant 26 would be chosen todeposit a residue that exhibited the desired properties, and again theexcitation is selected to reduce the reactant 26 to residue withoutcausing a change in the device material.

In an alternative embodiment, the second mechanism to remove or depositmaterial is accomplished through a photochemical effect. In thismechanism, the reactant is excited in a manner that causes it to changein chemical property or composition. In one example, the reactant 16 maybe changed by the energy source to an alternative material thatchemically reacts with the device material. In another example, thereactant 26 can change forms, for example, from liquid to solid, byactivating a catalyst in the reactant mixture that causes a chemicalchange of the reactant material. In this manner, a conducting orinsulating material may be added to the device material. Thiscompositional change may also be accompanied by a change in opticaltransmission of the reactant (e.g., from transparent to partially orcompletely opaque). Again, the level of the EM energy and or thewavelength is selected to excite the reactant to a level that induceschemical reaction without directly affecting the device material. In thecase where the EM energy is light, a tunable laser or other source canbe employed. The wavelength of the tunable source can then be adjustedto a wavelength that causes the reaction to proceed at an acceptablerate.

By selecting different reactants, sample materials could be removedwithout disturbing surrounding or underlying sample materials of adifferent type. Additionally, the selection of materials may be madesuch that certain types of layered samples may have a layer that can beused to stop the etching process. Thus, a so-called “etch stop” layer inthe target device may be part of the process. This layer is composed ofa material that does not react significantly to the etch solution orsolid and therefore allows a process whereby the etch material alongwith the excitation energy reacts with the first layers encountered butthe etch process will cease or be substantially slowed when the etchstop layer is reached.

Typical materials that may be used with the present invention are asfollows:

TIP SUBSTRATE MATERIALS MATERIALS REACTANTS Silicon Silicon PotassiumHydroxide Silicon Dioxide Quartz Sodium Hydroxide Silicon NitrideSilicon Dioxide Sulfuric Acid Carbon Aluminum Hydrofluoric Acid TantalumNitride Aluminum Oxide Ferric Chloride Silicon Carbide Zirconium OxidePhosphoric Acid Tungsten Carbide Molybdenum Silicide Sodium NitrateChromium Nitric Acid Tantalum Nitride Perchloric Acid Silicon doped withgroup II or III elements Silicon doped with group IV, V or VI elementsTitanium Ceric Amonium Nitrate Copper Sodium Chloride Iron, SteelGermanium Potassium Sulfate Carbon Buffered Hydrofluoric AcidCombinations of Hydrofloric Nitric, and Sulfuric Acids

These lists are not all-inclusive but are representative of types ofelements, oxides and metals for tips and substrates and hydroxides,acids, and compounds for reactants.

One example of the present invention would be to remove material from asurface of a device such as silicon. Reactants that have been found toproduce removal of silicon are potassium hydroxide and sodium hydroxide.In the present invention, an amount of the reactant, potassiumhydroxide, is taken from a source by the probe tip 14 of a scanningprobe microscope assembly 10 and then placed in the desired position.Once into position, the amount of potassium hydroxide that is located onthe surface is then subjected to the EM energy, which in this example isa focused argon ion laser with laser power of approximately 1.5 Watts.Once subject to the EM laser, removal of the materials is substantiallyconstrained to the location of the potassium hydroxide by the probe tip14.

It has been found that sodium nitrate serves generally as an effectiveremoval reactant for metals. Phosphoric acid, sulfuric acid andpotassium hydroxide serve as an effective removal reactant for stainlesssteel and titanium.

FIG. 3A shows a scanning probe microscope probe assembly 10 drawing anamount of reactant from a reactant pool 30, which is held in a reactantcontainer 32. FIG. 3B shows the probe tip 14 carrying an amount ofreactant. Surface forces are used, in the preferred embodiment, to causereactant from the reactant container 32 to adhere to the probe tip 10 ofa scanning force microscope assembly 10 while the reactant 16 istransported to the target device surface 18 or substrate. The tipmaterial and the reactant 16 are selected from a group of materials andreactants where the tip material is at least partially hydrophilic tothe reactant. Additionally, the substrate material may be hydrophilic tofacilitate transfer of the reactant from the tip to the substrate.

Tip 14 can be coated with a hydrophobic insulator 33 and still able toattract reactant 30. In this method, the tip 14 may be charged oppositeto a charge placed on reactant 30. When the charge difference issufficiently great, reactant 30 will be attracted to tip 14 withsufficient force that cohesion and gravitational forces are overcome.Reactant 30 may then be transported to the sample 18. The insulator 33prevents charge dissipation between reactant 30 and tip 14. As the tip14 is brought close to sample 18, the charge difference between reactant30 and sample 18 neutralizes and the hydrophobic nature of insulator 33drives reactant 30 towards the sample 18. The reactant 30, in thisembodiment, may be either a solid or a liquid.

In an alternative embodiment, the tip 14 is coated with the reactant ora component of the reactant 34 or is fabricated out of reactantmaterial. The reactant 34 can then be transferred to the surface 35 bydirect contact of the tip 14 to the device surface, as shown in FIG. 8C.The tip 14 could also be placed into a liquid, in a similar manner asdescribed for transfer of a liquid reactant, to complete the reactantmixture or aid in transfer of the reactant. In this embodiment, aportion of the tip coating is dissolved in the liquid, as shown in FIG.9A and the resulting reactant transferred to the substrate with thereactant 34. In this embodiment, the tip would need to be replaced morefrequently in order to effectively transfer the reactant 34.

In an alternate embodiment of the present invention, the transfer ofreactant 16 to and from the tip may also be facilitated by creatingelectric charge on the tip and/or the substrate. Also, in thisembodiment a portion of the sacrificial tip is transferred to thesubstrate. Subsequently, the EM energy is directed at the transferredmaterial and the transferred material changes to its final state.

FIG. 4A shows a scanning probe microscope assembly 10 with the probe tip14 depositing the subtractive reactant 36 onto a surface. In thisfigure, the reactant 36 is being deposited into a dimple 37 that waspreviously created with a previous application of the reactant 34. FIG.4A includes a targeted device 38 that includes multiple layers ofdiffering materials. These multiple layers are first device layer 40 andsecond device layer 42.

The dimple in the material 37, shown in FIG. 4A could also have beencreated by an alternative method, prior to using the reactant processfor additional material removal. For example, the dimple 37 could havebeen created during the processes used to create the device. The dimple37 could also have been created with the scanning probe tip 14 by directtip to surface contact. Other means of creating the dimple 37 or pitinclude the use of an ion beam or laser beam. The predefined dimplecould be used to help guide the reactant to the ideal location duringplacement. The location could also help constrain the reactant to thedesired location during the removal or additive process. In addition,dimples predefined during fabrication of the device could have highpositional accuracy relative to other non-accessible structure in thedevice.

The repeated application of the subtractive reactant 36 in FIG. 4A isdone to achieve a clear connection to device layer two 42. Due to thethickness of the first device layer 40, multiple applications of thesubtractive reactant 36 are needed to accomplish this goal.

In similarity to the FIG. 1A-1D, once the subtractive reactant 36 ispositioned on the surface, which in this figure is the dimple creation,the EM energy and the resulting beam 22 is focused, as shown in FIG. 4B,at the subtractive reactant 36 in order to remove additional material ofthe first device layer 40.

FIG. 4C shows the resulting void 44 created by the repeated applicationof the subtractive reactant. Additionally, it is noted that because ofthe differing materials in the device layers, the second device layer 42is a stop layer of material that is not reactive to the etchant. Inother words, the reactant chosen for the first device layer 40 does nothave the same effect of etching or removing material on the seconddevice layer 42.

FIG. 5A shows a scanning probe microscope assembly 10 positioningreactant into a surface dimple 48. In this embodiment, the technician isattempting to create additional matter on a surface that resulted from aprevious application of subtractive reactant 16.

FIG. 5A is the targeted device 38 as detailed in the FIGS. 4A-4C. Aspreviously detailed, the target includes a first device layer 40 and asecond device layer 42. Having removed the material as detailed in FIGS.4A-4C, the technician now needs to complete the connection.

FIG. 5B shows an electromagnetic source directing a beam 22 of energytowards the additive reactant 50. By subjecting the additive reactant 50to the beam 22, a more rapid chemical reaction of the additive reactant50 to the targeted surface is created.

FIG. 5C details the results of the beam on the additive reactant 50. Thebeam has caused the reactant to create a residue 52 that partially fillsthe void 54. A layer of material is now created by application ofadditive reactant 50 on top of a stop layer 55 of material.

FIG. 5D shows the resulting filled void 54 created by application ofadditive reactant 50. In this specific example, the additive reactant 50can create a connection to another objection on the targeted device. Forexample, if the target device is a semiconductor, the filling of thevoid 54 with the additive reactant 50 could be the connection of onetransistor to another transistor.

As can be seen from the present invention, there are endless amounts ofrepair or corrections that can be made to a device. To create such aconnection as that detailed in FIG. 5D, generally would require thecomplete creation of a new device. With the present invention, a companycan reuse or edit the device by simply modifying the surface with thetechniques disclosed therein.

FIG. 6A illustrates a multi-layer device. In this figure, there are fourlayers, a first device layer 40, a second device layer 42, a thirddevice layer 56 and a fourth device layer 58. The four layers, 40, 42,56, 58 are respectively silicon dioxide (SiO₂), silicon (Si), silicondioxide (SiO₂) and silicon (Si).

FIG. 6B illustrates a hole 59 that has been created through each of thefirst three layers 40, 42, 56. The hole 59, in this figure, is shownfilled with a nonconducting plug 60. To create a path way through thefirst device layer 40, a reactant such as buffered hydrofluoric acid isplaced on the layer by the scanning probe microscope assembly 10. Oncepositioned, a beam 22 is focused at the reactant in order to createetching or removal of the silicon dioxide material.

The buffered hydrofluoric acid reactant is not necessarily effective onthe second device layer 42, silicon. Therefore, this layer acts as astop layer and prevents the reactant from burrowing or etching into thesecond device layer 42.

If the second device layer 42 acts as a stop layer, then anotherreactant is chosen to continue the etching process through the device.For the second device layer 42, which is Si, a reactant that iseffective at removing the materials is sodium hydroxide. Like the firstdevice layer 40, the reactant is subjected to a beam 22 to remove thematerial. This process is continued until the necessary material isremoved to reach the third device layer 56, which is silicon dioxide. Toremove the material of the third device layer 56, the process, as in thefirst device layer 40, is repeated with buffered hydrofluoric acid asthe removal reactant for the silicon dioxide.

Once the necessary material is removed through all the layers, areactant is added in order to create a nonconductive residue 60. Thenonconducting plug 60 in FIG. 6B is created in order to make aninsulator for a subsequently created conducting plug.

FIG. 6C shows the next step in which the nonconducting plug 60 furtherhas a hole opened creating a path to the fourth device layer 58. As isseen in this figure, layer 42 is now insulated from layer 58.

FIG. 6D shows that the hole created in the insulator 60 in filled with aconductive residue 61. The device to create residue is similar to thatdetailed in relation to FIGS. 5A-5D. The connection, in this figure,makes a direct connection from the fourth device layer 58, silicon, upthrough the third device layer 52, second device layer two 42 and devicelayer one 40. The residue 61 is then located across the upper surface ofthe first device layer one 40 and onto their intended connections.

FIG. 7 shows that an opposite charge may be placed on the tip 14 andreactant 26 and substrate 18. This causes reactant 26 to be attracted tosubstrate 18. After placement of charge on tip 14 and sample 18, probe10 with reactant 26 is moved toward sample 18. When the distance betweenreactant 26 and sample 18 is sufficiently small coulomb forces willbecome greater than the surface forces holding reactant 26 to tip 14. Atthis distance reactant 26 will separate from tip 14 and move to sample18.

FIG. 8A illustrates a reactive coating 62 on the probe tip 14, which ispart of probe assembly 10. This figure depicts the probe assembly 10before it is brought to sample surface 18.

FIG. 8B illustrates the probe tip 14 with reactive coating 62.Additionally, this figure depicts the cantilever 10 lowering the tip 14to the sample surface 18.

FIG. 8C illustrates the instance when the probe tip 14 is raised fromsample surface 18. As the figure depicts, once the probe tip 15 isremoved an amount coating 63 remains on surface 18. This remnant ofcoating 63 becomes the reactant that is subsequently activated.

FIG. 9A illustrates the coated tip 14 that further includes a smallamount or droplet of reactant 16. In this embodiment, the reactant 16has reacted with the coating 62 to form a second reactant 64 as shown inFIG. 9B This mixture occurs as the droplet is transported from thesource of reactant to the surface.

During the transportation of the reactant, this second reactant, in mostinstances, contains dissolved parts of coating 62. Once transported tothe desired area, the second reactant 64 is placed or located on thesample surface 18.

FIG. 10A shows a probe assembly 65 including a cantilever 66 and a tip68 in which the cantilever 66 and tip 68 have an interior channel 70.The interior channel 66 is depicted in this figure as dashed lines.

The channel 70 delivers a fluid reactant 72 as indicated in FIG. 10Bthrough the channel 70 to tip 68 in preparation for delivery of fluidreactant 72 to sample surface 18. As shown in FIG. 10C, the laser 20activates the drop of fluid reactant 72 after the reactant 72 is placedon sample surface 18. Depending on the type of reactant 72 selected, aportion of sample 18 is removed or a residue on sample 18 will remain asdepicted and described in FIGS. IA-1D and 2A-2D.

FIG. 11A is a top view of a substrate. This figure illustrates howspecific shapes are created in accordance with an embodiment of thepresent invention. More specifically, this figure shows the creation ofan approximate square void in the surface of sample 18. A number ofdroplets of reactant 16 are placed on the sample 18 by means of a tip(not shown). Electromagnetic source 20, as detailed in FIG. 11B, mayactivate the droplets one at a time or all together if the diameter ofbeam 22 is large enough to encompass all the droplets. If reactantdroplets 16 have the sufficient viscosity then surface forces will beinsufficient to pull them together and they may all be placed on sample18. Reactant droplets 16 may then be activated all at once by laser beam22. Again, if reactant 16 has viscosity, then instead of placingreactant 16 in the form of droplets reactant 18 may be drawn into linesof various shapes. Such repeated applications of reactant 16 asdescribed here along with repeated applications of beam 22 will create avoid shape 74, as detailed in FIG. 11C, with high aspect ratio walls ofarbitrary depth in sample 18.

As can be seen, a wide variety of simple approximate shapes, such asrectangles can be created. The creation of more complex shapes may alsobe created using combinations of large and small rectangles, squares,circles and lines. Complex shapes may also be created in the depth aswell as in the lateral dimensions. By extension, complex additive shapesmay be created in elevation as well as laterally by the use of theadditive reactants previous described. Also, by extension an array ofapproximately circular holes or shapes located with precision relativeto each other or with precision relative to other features on sample 18may be created. Again, the reactant creating the array may be activatedat single locations sequentially or if the focused light spot is madelarge enough, the reactant may be activated in multiple locationssimultaneously.

The many features and advantages of the invention are apparent from thedetailed specification, and thus, it is intended by the appended claimsto cover all such features and advantages of the invention, which fallwithin the true spirit, and scope of the invention. Further, sincenumerous modifications and variations will readily occur to thoseskilled in the art, it is not desired to limit the invention to theexact construction and operation illustrated and described, andaccordingly, all suitable modifications and equivalents may be resortedto, falling within the scope of the invention.

1. An apparatus for modifying an object, comprising: a reactant that ispositioned on the object; and an energy device configured to direct itsoutput at the reactant in order to modify the object.
 2. The apparatusas in claim 1, further comprising an assembly that is configured toposition the reactant on the object.
 3. The apparatus as in claim 2,wherein the assembly is a scanning probe microscope.
 4. The apparatus asin claim 3, wherein the reactant is positioned with a probe tip of thescanning probe microscope.
 5. The apparatus as in claim 4, wherein thereactant is placed on the probe tip through a hydrophilic process. 6.The apparatus as in claim 1, wherein the energy device is anelectromagnetic device.
 7. The apparatus as in claim 1, wherein theenergy device is a laser.
 8. The apparatus as in claim 1, wherein theenergy device is configured to directed radio waves at the sample. 9.The apparatus as in claim 1, wherein in the object is a single layereddevice.
 10. The apparatus as in claim 1, wherein the object is comprisedof at least two layers.
 11. The apparatus as in claim 1, wherein theobject is a semiconductor device.
 12. The apparatus as in claim 1,wherein the reactant is configured to remove material from the object.13. The apparatus as in claim 1, wherein the reactant is configured toadd material to the object.
 14. The apparatus as in claim 13, whereinthe added material is a conductor.
 15. The apparatus as in claim 13,wherein the added material is an insulator.
 16. The apparatus as inclaim 11, wherein the reactant is selected based upon the object. 17.The apparatus as in claim 10, wherein one of the at least two layers isconfigured to act as a stop layer.
 18. The apparatus as in claim 10,wherein the reactant is configured to removed material from one of theat least two layers and not react with the second of the at least twolayers.
 19. The apparatus as in claim 11, wherein the energy device isconfigured to increase a reaction time of the reactant on the object.20. The apparatus as in claim 14, wherein the reactant is placed on theprobe tip through an electrostatic process.
 21. The apparatus as inclaim 17, wherein the added material is linked to another portion of theobject.
 22. The apparatus as in claim 11, further comprising a probeassembly and fluid delivery channel.
 23. The apparatus as in claim 11,further comprising a debris removal means.
 24. The apparatus of claim11, further comprising placing the reactant in multiple locations tocreate specific shaped features.